DuBois & King designed the replacement of an existing steel stringer bridge supported on one stone and one concrete abutment. Replacement design included load determinations and development of prestressing strand configuration for the new pre-stressed, precast concrete beams. Performed calculations and cost estimates and provided preliminary and final design, and construction phase services.
High Street Slope Stabilization
A landslide occurred on a steep slope between High Street and the Otis Falls Hydro impoundment on the Souhegan River following a prolonged period of heavy rain. High Street and one private residence were threatened by the potential for continuing slope failure. DuBois & King performed final slope stabilization design to include a sheet pile retaining wall at the top of the failure scarp and stabilization of the lower slope with rock riprap. DuBois & King provided bidding assistance to the Town. Services include FEMA Grant Application, data and field investigations, geotechnical investigations, survey, wetland mapping, consultation with sheet pile contractor, utility coordination, environmental permitting, coordination with nearby landowners and oversight agencies, preparation of easement plans, and construction phase administration.
Retaining Wall Assessment and Design
D&K completed assessment and design of several hundred linear feet of retaining wall damaged by Tropical Storm Irene. The wall supports a Town park adjacent to Roaring Brook and was severely undermined and damaged by flood waters from the storm. The firm performed subsurface soil investigations and developed design properties (allowable bearing capacity) from obtained field data using empirical data correlated from SPT blow count data. Firm staff also determined the proper substructure footing type and configuration. D&K conducted a visual inspection, coordinated with the Town and VTANR, and developed the design for replacement of the wall.
Ottauquechee River Retaining Wall-Building Demolition
Design of repairs to existing retaining walls along the Ottauquechee River in the Village of Quechee, Vermont. An approximate 50-ft length of existing retaining walls, divided between two areas, were partially undermined and damaged during Tropical Storm Irene in 2011. D&K conducted a field investigation to determine the extent of the scour, designed plans and specifications to repair the damaged areas, and assisted the Town of Hartford through the bid and construction phases. Repairs included new concrete toe support for walls and facing. The project was funded through a Community Development Block Grant and through FEMA’s Hazard Mitigation Grant Program. This site was the former location of the Quechee Reality building that was severely damaged during Irene. D&K provided engineering services for the demolition of the building.
North Street Retaining Wall
DuBois & King conducted engineering and construction phase services to reconstruct a failing retaining wall located on North Street near the street intersection. The existing retaining wall was a metal bin-wall with chrysotile asbestos coating. The wall, constructed in 1981, had reached the end of its design life and showed signs of deterioration. North Street is located immediately adjacent to the bin wall, and the street and traffic would have been compromised had the deterioration of the wall continued.
The replacement retaining wall consists of precast segmental block concrete construction. The new wall is approximately 12 ft high and 70 ft long and is consistent with AASHTO and Vermont Agency of Transportation standards. The wall also protects the existing water main and local services. D&K assisted the City throughout the bid, preconstruction, and construction phases of the project.
Professional services included:
Field topographical survey
Geotechnical investigation (coordinated with drilling contractor and laboratory testing of soil)
Preparation of construction level plans
Preparation of opinion of probable construction costs
Bid phase assistance
Assistance with construction contract execution
Review of contractor submittals
Schedule and attend pre-construction and progress meetings
Construction observation and field quality control
Provision of final record drawings